The paper addresses an interesting topic related to the physical and chemical processes that determine the atmospheric levels of the secondary inorganic aerosols (SIA) in urban scale. The manuscript is very well written. The scientific tools used (i.e. Eulerian modeling and PM chemical composition measurements) and methodological approach are robust, while the conclusions are clear.

The paper can be accepted for publication. The main minor comment is that the authors should provide maps with the chemical speciated total emission fields (precursors of SIA and SIA), so as to be easier to associate the impact of emission sources on the spatial distribution of SIA concentrations. For the same reason, the relative contribution of emission sectors on the precursors of SIA and SIA total emissions should be presented.

The manuscript describes the coupling of the EPISODE-CityChem cityscale CTM with the ISORPPIA thermodynamic model to account for SIA and acidity levels over the Greater Athens Area for a year of simulations in 2019. The manuscript is easy to follow and well-structured. However, it lacks description and discussion of two major factors that influence the interpretation of the results, being the emissions and meteorology, which I list in my below comments. The manuscript can be published in ACP when these are addressed.

Line 199: the improved spatial distribution of the CAMS emissions should be shortly described.

Lines 212-213: Representation of sea-salt as purely NaCl vs. explicit composition could be a bit further explained. Why is it not represented with explicit composition throughout the model?

How about biomass burning emissions other than domestic wood burning, i.e. forest fires? The area of interest is largely impacted by fires in certain periods. Same question for biogenic VOCs, are they taken into account?

Are local and international shipping emissions taken into account? The area is highly influenced by maritime emissions.

How about the vertical distribution of anthropogenic emissions? Are they all assumed to be all emitted at the surface?

How about the temporal distribution of emissions into hourly variation represented in the model?

Section 2.1.5: Are the meteorological simulations evaluated against observations? In particular wind speed can be very challenging over urban areas. How the WRF model is setup in terms of physics should be documented.

Section 3.1.1:

Can the reasons for low temporal correlation (r=0.46) be explained? Are they attributed to the temporal variation of the anthropogenic emissions for example?

Overall, the temporal and spatial distribution and performance of the model in SIA and acidity is strongly linked with meteorology and further discussions are needed on how the WRF model represents the meteorological conditions (see comment for section 2.1.5).